1. Field of the Invention
The present invention relates to a tool position correcting device capable of correcting the position of the cutting edge of a tool on a machine tool.
2. Description of the Related Art
A tool position correcting device disclosed in JP-A No. 3-35906 comprises a draw bar or rod supported for axial movement in the central bore of the spindle of a machine tool, an eccentric tool holder or eccentric rotary member supported on the nose of the spindle for rotation about an eccentric axis displaced from the axis of rotation of the spindle, and a motion converting mechanism, such as a screw mechanism, interlocking the draw bar and the tool holder to convert an axial motion of the draw bar into a rotational motion of the tool holder. The tool holder is turned by axially moving the draw bar to vary the radial distance of the tool held on the tool holder from the axis of rotation of the spindle to correct the position of the cutting edge of the tool.
In this known tool position correcting device, the tool holder is supported on the spindle with its back end fitted in bearings fitted in the holder support hole of the spindle and hence the tool holder can be turned by a comparatively small torque when correcting the position of the cutting edge of the tool. However, the force holding the tool holder on the spindle is not very large and hence the tool position correcting device is unsuitable for holding a tool for heavy machining.